The present invention relates to a method for improving the quality of an aliment, such as an alcoholic liquor, by removing therefrom an impurity, and more particularly to such a method for use where the impurity is a carbamate, sulfite or bioamine.
Urethan (also known as urethane, carbamic acid ethyl ester, ethylcarbamate, etc.) is a common carbamate in beers and wines. It is a naturally occurring product of yeast fermentations and arises from the reaction of various carbamoyl compounds and enzymatically-produced ethanol. These reactions account for most of the urethan present in beers and wines. Urethan may also be generated during the aging of wines and beers as a result of interactions of these beverages with the structural materials of the barrels and vats in which they are stored, often for long periods of time. Urethan is also present in distillates of beers and wines, some of that urethan arising from chemical interactions between ammonia, carbon dioxide and ethanol at the elevated temperatures required for the economic production of distilled beverages.
Urethan is now considered by the Environmental Protection Agency of the United States as a cancer suspect or carcinogenic agent, and urethan levels in beverages are regulated in several countries. For example, current regulations in the U.S. restrict its acceptable concentrations to 10 ppb (parts per billion) for table wines or 14 ppb for fortified wines. While there is some uncertainty as to whether urethan is itself the ultimate carcinogen or whether its metabolites or oxidation products are the carcinogenic agents, the further reduction, or ideally the total elimination, of urethan is considered highly desirable, but is limited by the available economically feasible technologies for doing so.
By way of background, the prior art suggests the removal of urethan precursors from beverages, for example, by treatment with urease enzyme to hydrolyze the precursors into ammonia and carbon dioxide, thereby to prevent urethan from being formed during the heating of the precursors and ethanol during pasteurization. However, the urease enzyme is inhibited by phenols, such as those frequently present in mashes from both grains and grapes, by ethanol (a desired fermentation product) and by sulfur dioxide (a natural constituent of beers and wines resulting from the fermentation of yeast and frequently present in wines as a result of the means used to decontaminate the barrels and vats used during fermentation). Additionally, the enzymes are rarely totally pure and frequently contain by-products which affect bouquet, taste and the like, and may even, if insufficiently purified, contain harmful bacteria therein. Urethan is a particular problem in connection with distilled alcoholic beverages, as much urethan is formed during the distillation process itself in addition to the smaller amounts generated during fermentation. Because they contain carbamoyl compounds, beers or mashes of necessity contain high amounts of the very reactants which produce urethan: ammonia, carbon dioxide, and ethyl alcohol.
Other undesirable carbamates frequently present as a food or liquid contaminant include the N-methyl carbamates used in pesticides and fungicides.
The term "sulfites" as used herein includes the salts of sulfurous acids (M.sub.2 SO.sub.3), acid-sulfites (MHSO.sub.3, also known as bisulfites), sulfur dioxide (SO.sub.2, also known as sulfurous acid anhydride), metabisulfites (M.sub.2 S.sub.2 O.sub.5), hydrosulfites (M.sub.2 S.sub.2 O.sub.4) and the like. Storage kegs often are sterilized with burning sulfur candles, and the resulting sulfite can find its way from the keg into hard liquors to which it is not added purposefully. Sulfites are intentionally used extensively in the treatment of alcoholic beverages (such as wines) and some frozen vegetables as well as in the treatment of foods and non-alcoholic beverages (such as some fruit juices). The sulfites are used as color stabilizers and as preservatives to preserve the products against spoilage due to bacteria and fungi. Wines contain about 3 ppm (parts per million) sulfur dioxide produced by yeast metabolism and additionally up to 30 ppm of sulfites added purposefully during wine making. While some of the actions of the sulfites are highly desirable (e.g., color stabilization, preservation, and the like), many of the sulfite actions are highly negative (e.g., allergic reactions with occasional consequent deaths, inactivation of particular protein-carbohydrate linkages, bronchial constriction and irritation, possible carcinogenicity, and the like). While U.S. government regulations require wines sold in the U.S. which contain more than 10 ppm equivalents to be labeled as "contains sulfites", there is great pressure to continue the use of sulfites in the wine industry as a color stabilizer and preservative.
The term "bioamines" as used herein includes the various organic amines such as tyramine, histamine, methylpropylamine and phenethylamine. Bioamines are believed to be a significant factor in the development of a "hangover" after alcohol has been consumed, especially in the form of wines. Additionally, the bioamines naturally present in fish (e.g., choline and trimethylamine) are a significant factor in the production of the characteristic fishy smell associated with stored or frozen then thawed fish. Thus there are clear advantages to the removal of bioamines from various aliments.
While the desirability of removing carbamates, sulfites, bioamines and like impurities from various aliments (e.g., solid foods, alcoholic and non-alcoholic beverages, ingestible fluids, drugs and the like intended to be taken internally) appears obvious, the requirements imposed upon the agents used to remove the same are manifold and arduous. To be acceptable, such an agent must be economical to use, have a very high affinity for the impurity, be insoluble in the beverage, not contribute any substances of its own to the beverage, and be inert in terms of affecting the color, taste or composition of non-offending substances in the beverage.
The term "aliment" as used herein refers to a substance taken into the body and includes both low alcohol, high alcohol, and non-alcohol beverages (e.g., fruit juices) as well as solid foods (whether frozen or not), drugs (whether ingested or injected) and the like. For solid foods, sulfites and bioamines are a major problem, while carbamates are not. For drugs, sulfites are a major problem but, since they are used to stabilize drugs, they are preferably not removed until immediately prior to use either by ingestion or injection. The preferred late removal of sulfites from drugs thus parallels its preferred late removal from various foods and beverages where its stabilizing effects are desired until just prior to consumption.
The term "impurity" as used herein refers to any undesriable or unwanted component of the aliment, whether naturally occurring or added for some purpose.
Accordingly, an object of the present invention is to provide method for improving the quality of an aliment by removing at least one impurity therefrom.
Another object is to provide such a method for improving the quality of an alcoholic liquor by removing therefrom an impurity.
A further object is to provide such a method for improving the quality of an aliment by removing an impurity selected from the group consisting of carbamates, sulfites, bioamines and combinations thereof.
It is also an object to provide such a method which economically removes the impurity without degrading the quality of the aliment.